The Radisson is about two blocks (long blocks) from the parks. You can walk or take a shuttle.
Hard to tell with the weather; this January has been COLD in Southern California. It's 34 degrees this morning. We'll be lucky to reach 60 today.
Typical weather (if there is such a thing!) in Febuary is highs in the 60s and lows in the 40s at night. We do get the occasional heat wave in February where it could be in the 80s. I'd check the forecast right before you leave and pack accordingly.
Enjoy!
